Let me bump this, with a plea for hankadam to tell us what he knows... or can find out from his sources.

This is the locomotive proposal referenced in the September 1950 issue of Popular Science (which can now be read courtesy of Google Books). There it indicated (with whatever accuracy Popular Science sources have) that the gasifier locomotive would be 4000hp, and was a project between PRR and "Lima".

Here is where the plot thickens, perhaps interestingly: A considerable amount of research, and key patents, map to General Machinery in Hamilton, OH (which unless I'm mistaken is related to the Hamilton Engine that Lima acquired). For example, the history of patent 2600251, for a free-piston engine starter (an important technical consideration in design for these engines) indicates the filing was Dec 6, 1945, but the patent actually issued, assigned to BLH, in 1952 -- this indicates to me that the concept was still under active development at BLH at that time, albeit perhaps only for ship propulsion. Other patents are 2434280, 2497091, and 2671435. (There are more, but I can't find my notes).

Plot thickens still more. See the paper by Commodore Lisle F. Small on 'free piston gas generator brightens gas turbine future' ... and recall that he joined Lima-Hamilton as Director of Research in 1948.

Can't help but wonder whether this chain of research might have influenced first the acquisition of Hamilton by Lima, and then of Lima by Baldwin. Scott Trostel might have covered this in his historical research of the Baldwin corporation.

The obvious poster child for 'conversion' to a free-piston locomotive is the two-unit GE turbine, conveniently of 4000 rated hp and tested on PRR, that had proven troublesome... largely due to excessive combustion-heat damage to the turbine blading and high net shp consumption by the compressor, both of which are 'solved' by the free-piston gasifier... it would have been comparatively simple imnsho to have installed several gasifiers of appropriate size to align with the existing power-turbine stage (which, iirc, was physically separate from the compressor and combustors in the GE turbine design). Might have been some corporate politics involving this, though, including whether BLW's long-standing relationship with Westinghouse over turbine design would make things difficult...

There is little question about where the problems would come in, though, as we have reports from the ship community about at least one big problem -- noise. In an ASME paper from 1954, McMullen indicated "air intake pulsations could cause unpleasant conditions in the engine room if the dimensions of the space were such as to produce resonant conditions within the operating speed range". These were S.I.G.M.A. GS-34 gasifiers, and tource of the noise reported was the INTAKE ducting to the gasifiers, which was light steel. Similar issues were reported for the gasifier plant applied to the SS William Patelson in the Liberty Ship Engine Conversion Project, where the issue of 'high pulsations in the engine room' were only addressed with 'high repair and redesign costs', and the gasifiers were derated from 1000 to 800 nominal hp each.

I for one will be VERY interested to hear a Rentschlerian version of this project...

Yes, "General Machinery" was the Hamilton half of Lima-Hamilton (and so, after another merger, the Hamilton "third" of BLH), so this is a relevant connection, one I also would love to know more about.

Note that EMD also had a free-piston gasifier project, maybe a bit later: there was discussion (that went far enough for detailed worrying about weights and/or clearances) of building a test/demonstrator locomotive for the Union Pacific, which ***MIGHT*** have been in a variant of the FL-9 carbody.

I'm not sure what you are referring to when you write:"The obvious poster child for 'conversion' to a free-piston locomotive is the two-unit GE turbine, conveniently of 4000 rated hp and tested on PRR, that had proven troublesome..."The only two-unit GE turbine locomotive in the relevant horsepower range I am aware of was the two-unit steam turbine electric built before WW II for the Union Pacific. I think a better starting point for the Lima project might have been the Westinghouse 4,000 hp gas turbine locomotive of the late 1940s, but this was a single unit (with B-B-B-B running gear).

The September 1975 issue of "Trains" had a collection of drawings of un-built motive power projects, including "Lima-Hamilton's proposed 3200 h.p. free-piston gas-turbine-electric C-C unit." The artwork suggests something vaguely like an E-unit or Alco PA carbody, with a strange treatment of the nose area that looks inspired by the PRR's GG-1.

There's a bit of discussion of the EMD project on the EMD forum, in a string titledUnbuilt (but proposed) FG-9 locomotivecurrently about half way down the first page. A couple of references, but no further information about the Lima project.

Must be a senior moment. I was going by the postings on Will Davis' blog, which I thought showed a double-unit GE locomotive I hadn't seen before. Indeed I hadn't... it's as you indicate, the Blue Goose, and only one unit. (Perhaps I was confused by the diesel picture at the top of the blog pages!) Certainly would make 'more' sense for BLH to convert its 'own' --

Meanwhile, perhaps peripherally, there was quite a bit of interest in the free-piston engine for railroad service during this period, when the weight, complexity, and precision required for large-hp diesels was still high, and the issues regarding TIT for 'conventional' Brayton-cycle turboshaft engines still critical. Note that a (properly-designed) free-piston engine has many of the attractive characteristics of a piston engine at high 'turndown', while keeping determinate combustion processes -- it does this by regulating the number of strokes per minute, but each stroke takes the same cycle time to complete. It would also appear that even at very high effective combustion ratio (1:50 peak!) there is limited tendency to NOx generation.

On Pescara's son's site, there is a quote from a French journalist, apparently (to my poor French-reading eye) part of an entry in an encyclopedia of science and technology, in which I think he is claiming a sfc of 155g/CV/h (and overall 180-200 g/CV/h, presumably with electrical transmission). He also appears to note some intriguing thermal efficiencies: 72% for the gasifier, "85%" for the transmission (which is the same figure quoted in Ransome-Wallis for contemporary DC/DC electric transmission) and 65% for the overall system. Someone comfortable with engineering French should look this over and perhaps translate the relevant sections accurately (there is also a nice drawing of one of the SG-34s on one of the pages over there...)

I believe there are a couple of SAE papers that touch on the GM 'locomotive' gasifier design that would have gone into the "FG-9" - is there someone out there with cheap access to this material? I'd expect the design to be associated with the people doing the Hyprex engine research; I don't know enough about contemporary GM structure to recognize how the politics of coordination between divisions (e.g. as seen between the locomotive and bus divisions on the Aerotrains) would have worked for coordination.

One potentially interesting detail is the apparent requirement for five carrying axles, only powering four, on a gasifier locomotive, when one of the quoted salient advantages of gasifier tech at the time was that the net plant weight (gasifier equipment plus turbine) was less than an equivalent diesel engine. About the only thing I can think of is that the locomotive required an extended chassis, but the weight distribution couldn't be equalized on the longer frame... but the frame didn't need to be as long as an E unit. Ahhh... engineering speculation, ain't it fun?

Overmod-- I'm an "adjunct" at a university: they don't pay me, but I have library privileges. I'll ask (next week) whether there is an easy way to get SAE papers... If there is, can you provide detailed references? I've never looked for SAE stuff before, so don't know anything about numbering or...

A primary reference would be Achten's paper from 1996 (941776). The thing that I think is the keystone of this question is a paper by Hans George Spier on 'Supercharging in the Free-Piston Cycle", which is paper 590035 (Jan 1 1959, which is VERY late for BLH engine development, but interestingly timed relative to the locomotive turbocharging experimentation going on in the runup to 'second-generation' diesel power...

Less than a half-hour here should give you quite a list of things to go after... not all of which, perhaps, are on the direct topic, but might be fun to see... Eric Hirsimaki, for example, might have some fun with 830554, which unless I profoundly misunderstand things is hinting at the use of coal-based fuel in a diesel engine...